Software Quality Models

1. Software Quality Assurance Software Quality Models

2. Outline • McCall’s Quality Model (1977) • Boehm’s Quality Model (1978) • FURPS/FURPS+ • Dromey's Quality Model • ISO Models (ISO 9126) • Capability Maturity Model(s) • Six Sigma Software Quality Assurance (SQA)

3. McCall’s Quality Model • Three major perspectives for defining and identifying the quality of a software product: • Product Revision (ability to undergo changes), • Product Transition (adaptability to new environments) and • Product Operations (its operation characteristics). Software Quality Assurance (SQA)

4. McCall’s Quality Model • The model details the three types of quality characteristics in a hierarchy of • 11 Factors, • 23 Quality Criteria and • Metrics Software Quality Assurance (SQA)

5. McCall’s Quality Model Software Quality Assurance (SQA)

6. McCall’s Quality Model Software Quality Assurance (SQA)

7. Boehm’s Quality Model • Similar to the McCall Quality Model • Presents a hierarchical quality model structured around • High-level characteristics, • Intermediate level characteristics, • Primitive characteristics Software Quality Assurance (SQA)

8. Boehm’s Quality Model Software Quality Assurance (SQA)

9. McCall’s & Boehm’s Quality Models: a comparison Software Quality Assurance (SQA)

10. FURPS/FURPS+ • Similar to the McCall’s and Boehm’s Quality Models • Divides quality attributes into two • Functional • Nonfunctional Software Quality Assurance (SQA)

11. FURPS/FURPS+ • Functionality – which may include feature sets, capabilities and security • Usability – which may include human factors, aesthetics, consistency in the user interface, online and context sensitive help, wizards and agents, user documentation, and training materials • Reliability - which may include frequency and severity of failure, recoverability, predictability, accuracy, and mean time between failure (MTBF) • Performance - imposes conditions on functional requirements such as speed, efficiency, availability, accuracy, throughput, response time, recovery time, and resource usage • Supportability - which may include testability, extensibility, adaptability, maintainability, compatibility, configurability, serviceability, installability, localizability (internationalization) Software Quality Assurance (SQA)

12. Dromey's Quality Model • Similar to the McCall’s, Boehm’s and the FURPS(+) quality model, • The basic idea is: “quality evaluation differs for each product” Software Quality Assurance (SQA)

13. Dromey's Quality Model Software Quality Assurance (SQA)

14. Dromey's Quality Model • Dromey's Quality Model is further structured around a 5 step process: • Chose a set of high-level quality attributes necessary for the evaluation. • List components/modules in your system. • Identify quality-carrying properties for the components / modules (qualities of the component that have the most impact on the product properties from the list above). • Determine how each property effects the quality attributes. • Evaluate the model and identify weaknesses. Software Quality Assurance (SQA)

15. ISO 9126 Standard Quality Model • A deviation of McCall’s Factor-Criteria-Metric Model • Established in 1993 • Defines software quality as: “The totality of features and characteristics of a software product that bear on it ability to satisfy stated or implied needs.” Software Quality Assurance (SQA)

16. ISO 9126 • Quality is decomposed into six factors: • Functionality • Reliability • Efficiency • Usability • Maintainability and • Portability Software Quality Assurance (SQA)

17. ISO 9126 Software Quality Assurance (SQA)

18. Comparison Software Quality Assurance (SQA)

19. Outline • McCall’s Quality Model (1977) • Boehm’s Quality Model (1978) • FURPS/FURPS+ • Dromey's Quality Model • ISO Models (ISO 9126) • Capability Maturity Model(s) (TBD) • Six Sigma (TBD) Software Quality Assurance (SQA)

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21. Software Quality Assurance Software Quality Models